Heat exchange devices



y 1965 w. RASKIN 3,251,410

HEAT EXCHANGE DEVICES Filed Jan. 8, 1965 United States Patent 3,251,410 HEAT EXCHANGE DEVICES Walter Raskin, Brooklyn, N.Y., assignor to Dean Products Inc., Brooklyn, N.Y., a corporation of New York Filed Jan. 8, 1965, Ser. No. 425,116

1 Claim. (Cl. 165-181) This application is a continuation-in-part of copending application Ser. No. 241,869, filed Dec, 3, 1962, and now abandoned.

This invention relates to heat exchange devices and more particularly to heat exchange elements used in heating, cooling and refrigerating, such as is shown, for example, in my Patent No. 2,434,519.

It is an object of the invention to provide a primary surface tube with confluent ribs over which is fitted a plurality of spaced secondary surfaces in the form of fin plates.

It is an object of the invention to provide a tube and fin combination of this character to give more effective total heat exchange surface in a given space and to provide relatively greater strength to the heat exchange element.

' It is an object of the invention to provide a tube in which constant contact will be consistently maintained between the tube and thermal conducting fin plates borne by it and by which a relatively equal distribution of heat transfer for the full area of the fin plates will be attained.

It is an object of the invention to provide heat exchange elements in which a ribbed tube will have hollow radial extensions projecting for a substantial distance into the fin plates borne by it as an aid to economical distribution of the heat transfer action throughout the full areas of the fin plates.

It is an object of the invention to provide means by which any decomposition of adjacent parts of the ribbed tube and the fin plates fitted thereon will be. compensated for, and the assurance of good contact between the parts of the tube and the fins will be had.

More particularly, the invention contemplates the provision of a tube formed with a central cylindrical fluid passage and a plurality of radially extending hollow ribs arranged in a matching pattern around the cylindrical passage. The invention contemplates an arrangement of a plurality of spaced fin plates closely embracing the periphery of the tube, with the center ends of the hollow ribs terminating inwardly of the outer edges of the fin plates, each of the fin plates having a centrally-located round hole and radially extending slots projecting from the hole, the hole and the radial slots of the fin plates embracing the periphery of the tube and providing the sole peripheral support of the tube so that the tube is thereby supported against thermal pressure and the fin plates are self-adjusting relatively to the tube to provide for maximum thermal pressure therebetween. The fin plates are of such shape that they provide a plurality of corners which are located radially outwardly of the hollow ribs to produce effective thermal distribution by the fin plates.

With these and other objects to be hereinafter set forth in view, I have devised the arrangement of parts to be described and more particularly pointed out in the claim appended hereto.

In the accompanying drawing, wherein an illustrative embodiment of the invention is disclosed,

FIG. 1 is a perspective view of a portion of the prime surface ribbed heat exchange tube with the secondary surface fin plates omitted therefrom;

FIG. 2 is a face view of one of the fin plates for application on the ribbed tube of FIG. 1;

FIG. 3 is a top plan view of a portion of the hollow ribbed tube of FIG. 1 with a number of the fin plates, such as is shown in FIG. 2, fitted on it;

3,251,410 Patented May 17, 1966 FIG. 4 is a front elevational view of the structure of FIG. 3 with the ribbed tube thereof being shown in section, and

FIG. 5 is a plan view of another embodiment of the invention in which the tube is provided with spirally arranged ribs, and a few of the fin plates are shown in position on the tube.

In the embodiment of the invention shown in FIG. 4, there is therein shown a tube 1 having a cylindrical central conduit portion 2 forming a passage for the heat exchange medium or fluid. There is provided a plurality of radially extending hollow ribs 3 formed integrally with the conduit portion 2. Four of these ribs are shown in the drawing, but this number may be increased or decreased as desired. These ribs are hollow or of doublewall arrangement, being provided with the spaced opposed walls 4, 4 to thereby provide for a slight spacing 12 between these walls, which spacing communicates at one end with the interior of the central cylindrical conduit tube. The outer end of each of the spaces 12 is closed by the band 5 located at the outer end of each of the formed ribs. The result of this construction is a hollow conduit provided with a plurality of hollow radial ribs capable of expansion under pressure within the tube.

,In the embodiment of the invention shown in FIG. 1, the ribs are arranged straight or in parallelism, while in the embodiment shown in FIG. 5, the ribs 6 therein shown are arranged spirally, as suggested in my Patent No. 2,434,519.

Arranged along the length of the ribbed tube 1 and at suitable equal distances apart if desired is a plurality of plates 7 constituting radially projecting fin plates. Each of these fin plates is provided with a central circular aperture 8 from which a plurality of radial slots 9 extend. These slots 9 conform in shape and in number to the radial ribs on the tube 1 and the central aperture 8 conforms in shape to the outer surface of the central conduit part 2, so that the fin plates 7 can thus be precisely fitted on the tube 1 and they will be nonrotatively mounted thereon as clearly shown in FIGS. 3 and 4. The slots are arranged, in the embodiment shown, to form. the diagonals of a square. When the fin plates are fitted on the tube as above described, there is a frictional engagement between the fins and tube for the purpose of eifecting an optimum of heat transmission between the tube and the fins. The central hole in each of the fin plates and the radial slots extending therefrom embrace the periphery of the tube and provide the sole peripheral support of the tube so that the tube is thus supported against internal pressure and the fin plates will be self-adjusting relatively to the tube to provide maximum heat transmission therebetween.

I am aware that prior to the present invention heat exchange conduits have been provided with fin plates. With that arrangement, chemical and physical deterioration often sets in between the surface of the tube and the peripheral edge of the holes in the plates through which the tube extends. In such a case, loss of uniform contact between the tube and its fins occurs; then the fin plates tend to loosen on the tube and the effective heat surfaces available is materially reduced.

In the present construction, the pressure of the heating or cooling medium within the flow passage or conduit 2 causes pressure to be imposed outwardly on the inside surface of the walls 4, 4 of the ribs, tending to cause the same to spread apart, within the radial slots 9 in the fin compensated for by the spreading apart of the walls of the ribs 3 under the internal operating pressure. As a result, with the described construction, greater tube 3 strength is maintained and good thermal contact between the tube of FIG. 1 and the fin'plates 7 applied thereon as herein described, will be constantly assured.

When platesor fins are applied to conventional cylindrical tubes, uniform thermal distribution for the complete surface of such plates is not always obtained. With the present construction, the considerable radial projection of the hollow ribs 3 toward the outer edges of each fin plate 7 is such that effective thermal distribution throughout the entire area of each fin plate takes place definitely. It is also to be noted that a ribbed tube of the type described, when embraced by a plurality of the fin plates 7, is materially stiifened, supported and strengthened. The described arrangement also provides low cost additional radiating surface for heat exchange, and provides for a more eificient use of the primary tube and the secondary fin surfaces. extra strength inherent in a fin and tube heat exchanger of this character is such as to enable greater heat transfer and to accommodate higher pressure with less weight and metal. It is to be noted that the corners of the fin plates are located radially outwardly of the ribs to produce efiective thermal distribution by the fin plates.

Having thus described an embodiment of the invention, it is obvious that the same is not to be restricted thereto, but is broad enough to cover all structures coming within the scope of the annexed claim.

What I claim is:

A tube for a heat exchange device wherein there are a plurality of spaced fin plates embracing the periphery of It has been found that the the tube; said tube having a central cylindrical fluid passage and radially extending hollow ribs arranged in a matching pattern around the cylindrical passage, the ends of said hollow ribs terminating inwardly of the outer edges of said fin plates, each of the said fin plates comprising a relatively flat sheet of metal having a centrally located round hole therethrough and slots extending radially from the hole, the relatively thin edges of said sheet at said hole and said slots closely and frictionally engaging the periphery of said tube and providing the sole support ofsaid tube, each of said plates having a plurality of corners, and each of said corners being located radially outwardly of a rib; wherein expansion of said ribs will cause said tube to tightly engage the edges of said hold and slots in said fin even when deterioration of the metal occurs and wherein the rib pressures occur at the corners of the plates for maximum strength and efiective thermal distribution.

References Cited by the Examiner UNITED STATES PATENTS 2,434,519 1/1948 Raskin ll l0 FOREIGN PATENTS 1,186,655 8/ 1959 France.

FREDERICK L. MATTESON, JR., Primary Examiner.

CHARLES SUKALO, Examiner. 

